Update on Seawall (James Larkin Road/Clontarf Road), associated S2S/Cycleway Project and Recent Flooding in this Area

Update on Seawall (James Larkin Road/Clontarf Road), associated S2S/Cycleway Project and Recent Flooding in this Area

Dear Resident

Thank you for previously contacting me regarding the seawall between the Wooden Bridge and Causeway Road (James Larkin Road/Clontarf Road).

I wish to now provide you with the latest update and am attaching for your attention the recent Part 8 advertisement from DCC regarding the matter of reducing the seawall height, and I would invite you to read this advertisement and be assured that I am monitoring matters closely and will be supporting this proposed reduction..

This seawall height reduction proposal is the culmination of a period of hard work and public pressure supported by you, and I want to acknowledge this to you and also the work put into this by members of Clontarf Residents Association, Clontarf Business Association, Save our Seafront and Raheny Tidy Towns. I also wish to recognise the tenacity shown by my colleague Councillor Damian O’Farrell on this matter.

There are several outstanding elements with regard to the S2S/Cycleway Project which my colleague Damian is pursuing including electricity connection for light poles and traffic lights at Dollymount Park as well as pedestrian crossings and landscaping.

Also in reference to the flooding that occurred on Saturday 27th May along the James Larkin Road, I would like to include below the response from DCC to Councillor Damian O’Farrell’s question submitted to DCC.

Thank you again for your interest in these matters and I will continue to monitor and update you on same.

Kind regards

Finian McGrath TD (Ind.)

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Question to the Chief ExecutiveCouncil Meeting 12th June 2017

Q.123 COUNCILLOR DAMIAN O’FARRELL

NCA To ask the Chief Executive to report and answer questions as regards the flooding and subsequent road closure of the James Larkin Road on Saturday 27th May. As part of the Sutton to Sandycove Cycleway & Footway Interim Work Project / Bull Road to Causeway Road (Part VIII) extensive drainage and flood prevention work was to be completed in this area. There was a Public Engagement Forum (PEF) set up in respect of this project and at the very first meeting (16th December) it was reiterated by local community groups and public representatives that the only flooding problems experienced in this area where fluvial, caused by the Naniken River and heavy rainfall. DCC officials assured the PEF that the proposed project would address this flooding issue.

The project design proposed to reinstate all surface water outfalls located along the proposed flood defence scheme, the surface water outfalls which facilitate sewer discharges were to be upgraded by the provision place additional overflow manholes and/or other appropriate measures. There were also drainage services associated with the lowering underground of the pumping station with effected existing gullies being relocated. Where build outs were proposed double gullies with separate connections would be constructed. As regards the Naniken River culvert, headwalls will be repaired, a valve flap provided as well as an extension of the Naniken stream culvert.

Is DCC satisfied with the drainage design provided by consultant engineers Roughan & O’Donovan? If DCC is not satisfied what remedies are provided for in the contract?

Is DCC satisfied with the drainage construction work carried out by the contractor KN Group? If DCC is not satisfied what remedies are provided for in the contract?

If DCC is satisfied with both the design and construction of the drainage element of the aforementioned Part VIII and was made aware of all the local fluvial issues what is the problem with the newly constructed drainage solution and also what is the solution?

What confidence can the public and elected reps have with forthcoming Part VIII projects being presented by DCC for approval?

Lastly, extensive ponding of water was identified in front of houses alongside Clontarf Road. This ponding was below the level of newly installed drains which were made the drains ineffectual. Can this matter be rectified as a matter of urgency please?

CHIEF EXECUTIVE’S REPLY:

We are satisfied with the drainage layout for the Dollymount S2S roadway designed by Roughan O’Donovan which more than doubles the previous number of road gullies.

We are also satisfied with the construction of the road drainage system constructed by KNN; once all of the road gullies are cleaned out at the end of the contract.

It is impossible to prevent road flooding completely in any part of the City it is only possible to reduce this risk. The Dollymount S2S cycle way is designed to cope with normal road way, cycleway and footpath rainfall once the tide is not too high and the flow in the Naniken river is at a reasonable flow rate. This were not the case on Saturday 27th May last.

Very heavy rain fell in this area from 11am. The Naniken river burst its banks in St. Annes Park near the upstream end of the duck pond and flooded around 400m of the park pathway beside the road and the adjoining field. River water then came out onto the road way through three gaps in the low park wall as shown on figure 1. This caused road flooding to a depth of around 250mm in places as shown on figure 2. The rain continued to be heavy in this area till around 2pm. The road drainage was performing as shown on figure3.

The flooding was exacerbated by a high tide which was approximately 1.8m Malin at 12noon, approx 2.15m Malin at 1.15pm (peak) and 1.4m approx at 3.15pm. The road level close to the duck pond is around 3.0m Malin.

Some debris was also washed out of the park which partially blocked the road gullies from 50m north of the pond to around 350m south of it. These were cleared by the Gardai and later by the drainage division and the roadway was then re-opened to traffic. The flood subsidence would have taken longer if the surface water drainage for the roadway had not been recently augmented.

Gaps on wall; which was originally 2m high with no gaps; resulted in water entering on to the James Larkin road way.